She 100% knew knew what she was doing when she repeatedly told 911 that it was an African American man.

If I recall, the police actually did respond to the call but when they showed up, both Coopers had left the scene. It is even more troubling that they responded to her call, since she didn't appear to give any more details to the 911 operator. Many people can't get the police to come out when they're in actual danger.